This invention relates to heat exchangers of the type formed from dish-shaped heat exchanger plates.
One form of plate-type heat exchangers includes a plurality of plates secured together in a stacked assembly with gaskets or bosses located between adjacent plates and traversing a course adjacent to the plate peripheries. Flow of two fluids involved in heat exchange is through alternate layers defined by the stacked plates. The stacked plates are typically joined together as a unitary structure by brazing the various components together. Examples of such plate-type heat exchangers are disclosed, for example, in U.S. Pat. No. 5,931,219 issued to Kull et al. and U.S. Pat. No. 4,872,578 issued to Fuerschbach et al.
A characteristic of previously proposed nested-dish heat exchangers is that in order to provide strength to the heat exchanger stack, the heat exchanger plates are typically sandwiched between a pair of thicker end plates. One of the end plates is typically nested within the flange of the final plate in the stack of the heat exchanger plates with the peripheral flange of the final heat exchanger plate extending a substantial distance beyond an outer surface of such end plate. Such a configuration can result in wasted space, namely, the area surrounded by the portion of the peripheral flange on the final heat exchanger plate that extends beyond the outer surface of the end plate. Additionally, the extending flange edge can provide a sharp edge such that care must be used in handling the heat exchanger to avoid injury to the person handling the heat exchanger. Accordingly, there is a need for a nested dish plate-type heat exchanger that reduces unused space. A plate-type heat exchanger which reduces the exposed peripheral flange of the final heat exchanger plate in the stack of plates is also desired.